The summer solstice marks the longest day of the year, or about 16 and a half hours of sunlight on average in the United States.

The amount of daylight hours depends on how far you live from the equator. In Anchorage, Alaska the solstice brings more than 19 hours of sunlight, while in Honolulu, Hawaii, it brings about 13 and a half hours of sunlight.

Usually the date falls on June 20. While the winter solstice transitioned neatly to modern holidays such as Hannukah and Christmas, there are few modern summer solstice celebrations.

But in ancient times, it was noticed and marked with rituals and festivals, said Anthony Aveni, a professor of astronomy and anthropology and native american studies at Colgate University.

In the spring, as the days approach the solstice, the sun “rises as far north as you ever get it, and setting as far north as you ever get it,” he told Travel + Leisure.

When this happens, there is more and more sun until the solstice, or the day when the sun stands still. The word solstice means “sun stand,” or “sun stands still,” Aveni pointed out.

“We don’t celebrate it so much, but in the ancient world they certainly did,” he said. “It was the time when they would worship the gods in hopes of a fruitful crop. Because they planted these crops in the summertime, so you would have festivals based on worshiping the sun when it’s at its fiery hottest.”

For example, in medieval Europe people would build a giant hoop out of straw and light it on fire, he said.

“They would roll it downhill from a mountain toward the river, the idea being to imitate the movement of the sun in the sky,” he said. “So they had fire festivals and fire rituals and other types of celebrations.”

The summer solstice was celebrated all over the world, because every ancient civilization recognized it was happening, he said.

“You can see these things,” he said. “We keep track of these on our calendars and our cell phones, but for people who live outdoors, they were very well aware of where the sun moves on the horizon during the course of the year.”

Aveni added that Stonehenge in the United Kingdom was a monument to the summer solstice.

“People still go there to watch the sun rise over the Heel Stone on June 21,” he said. “That’s when we can imagine 5,000 years ago, when it was built, that people would have walked up the causeway bringing all of their ritual apparatus to worship the sun when he was at his maximum height in the sky, the peak of his career if you will.”

Aveni said in modern times, summer solstice celebrations don’t get as much fanfare. He thinks that’s because the stress of the winter season took route more strongly, causing people to continue to have a need to celebrate in the winter season.

Winter is when people from across time have been “afraid something bad is going to happen,” he said.

“When you see the winter come and the sun begin to go far away, you worry that maybe it won’t come back,” he said. “That’s why you get these intense sessions of worshipping and paying homage to the gods.”